International Federation of Gynecology and Obstetrics

Transmission of cancer cells from a mother to her unborn baby is "a very rare problem", it has been claimed.

According to Sarah Montagu, administrative secretary at the Association of Radical Midwives, not only must the mother have cancer when pregnant - which is in itself unusual - but there also needs to be a rare mutation which 'masks' the cancer cells from the baby's immune system.

She was speaking after the Institute of Cancer Research used genetic fingerprinting to prove for the first time that an infant's leukaemic cells were unquestionably of maternal origin.

"It doesn't appear to be something which would happen to every woman who has the misfortune to have a cancer while pregnant," Ms Montagu commented.

"It therefore seems to be primarily of academic rather than practical interest."

She noted that in cases where cancer could be passed from mother to child, the newborn should be tested frequently for the development of such cells, enabling early treatment.